The purpose of this study is the direct investigation of IgE biosynthesis in the mouse utilizing new methods of assay of humoral and cellular IgE production. The first objective is to develop specific techniques to quantitate humoral and cellular IgE synthesis. Total and specific IgE will be quantitated by an alkaline phosphatase immunosorbent test. IgE bearing lymphocytes will be detected by immunofluorescence. IgE antibody producing cells will be determined by the indirect plaque-forming cell assay. These procedures will be used to determine host and environmental factors regulating IgE biosynthesis. IgE synthesis will first be investigated in different lymphoid organs and other organs known to contain IgE producing cells such as the lung and gastrointestinal tract. Utilizing this approach, the IgE response will be studied in different strains and age categories of mice. The effect of laboratory counterparts of environmental factors (such as pertussis and aluminum hydroxide adjuvants) as well as the role of antigen type, size, dose and route of administration in stimulating IgE production will be determined. Such studies should further our understanding of IgE synthesis in man.